Blowouts are the uncontrolled release of crude oil and/or natural gas from an oil well or gas well after pressure control systems have failed. Subsea wells have the wellhead and pressure control equipment located on the seabed. They vary from depths of 10 feet (3.0 m) to 8,000 feet (2,400 m). It is difficult to deal with a blowout in very deep water because of the remoteness and limited experience of researchers and scientists with this type of situation.
Oil or gas spills from blowouts cause extensive damage to marine and wildlife habitats as well as the fishing and tourism industries of the areas surrounding the spill. Skimmer ships, floating containment booms, anchored barriers, and sand-filled barricades along shorelines have been used in an attempt to protect hundreds of miles of beaches, wetlands and estuaries from the spreading oil. During a recent oil spill, it was estimated that 53,000 barrels per day (8,400 m3/d) were escaping from the well just before it was capped after three months.